With the development of computer technology, an image stored in a conventional recording medium such as a paper or a photograph is now treated in a computer as digital information. With the spread of personal computer, various images are converted into digital information. However, the conventional recording medium is still important. Accordingly, the digital information should be output as a visible image on the recording medium by an image recording process.
An ink jet method is a widespread image recording process for outputting digital information. The ink jet method has an advantage that a color image can be formed by an inexpensive apparatus (printer). It has been considered that the image quality of the ink jet printer is inferior to those of other printers (such as a thermal sublimation transfer method, an electron photographic method, a silver halide photographic method). However, the ink jet printer has recently been improved in resolution and gradation. The image quality of the ink jet printer is now comparable to those of the other printers.
The ink jet method uses an image recording medium. An ordinary paper or an ink jet recording paper has been used as the recording medium. The ink jet recording paper comprises an ink receiving layer provided on a paper (support). With the improvement of the ink jet printer, the conventional image recording medium now cannot exploit the full performance of the improved printer. The conventional image recording medium cannot deal with the high resolution of the improved printer because an ink is blotted in the conventional medium. With the improvement of the image quality, a glossy image like a photograph has recently been required. However, it is difficult to form a glossy image in the conventional image recording medium. Accordingly, the image recording medium should be improved with the improvement of the ink jet method.
The improvement of the image recording medium is proposed in Japanese Patent Provisional Publication Nos. 57(1982)-89954, 60(1985)-224578, 61(1986)-12388, 4(1992)-216990, 6(1994)-64306, 7(1995)-179032 and 8(1996)-24436.
Japanese Patent Provisional Publication No. 57(1982)-89954 discloses a recording material (a liquid absorbing sheet), which comprises a support, a liquid absorbing undercoating layer and a liquid permeable surface layer in the order. Japanese Patent Provisional Publication No. 60(1985)-224578 discloses a recording material (an overhead projector film), which comprises a support (a transparent base film made of a synthetic resin) and a transparent hydrophilic film made of a water-soluble polymer. Japanese Patent Provisional Publication No. 61(1986)-12388 discloses a recording material, which comprises an ink receiving layer and an ink permeable layer.
Japanese Patent Provisional Publication No. 4(1992)-216990 discloses a recording material, which comprises a support, a polyolefin layer and an ink absorbing layer containing gelatin and starch in the order. Japanese Patent Provisional Publication No. 6(1994)-64306 discloses a recording material, which comprises a support, a polyolefin layer and an ink receiving layer containing gelatin in the order. Japanese Patent Provisional Publication No. 7(1995)-179032 discloses a recording material, which comprises a support, a polyolefin layer and an ink receiving layer containing a synthetic hydrophilic resin in the order. Japanese Patent Provisional Publication No. 8(1996)-24436 discloses a recording material, which comprises a support and an ink receiving layer containing gelatin and a basic latex.